Hoeing machines or vineyard plows designed to work the ground between the trunks of trees or shrubs of a plantation planted in rows are known that have the goal of eliminating the useless plants that can grow between the trunks by breaking up the crust of the ground.
The invention involves machines of the type consisting of a working head mounted so that it turns around an axis oriented perpendicularly or approximately perpendicularly to the ground during work.
Known machines of this type (U.S. Pat. No. 4,332,299A, FR-1.577.988A, FR-2.683.117A, FR-1.469.298A) consist of a working head containing a horizontal rotary tool-holder driven by a hydraulic motor or by the power take-off shaft of an agricultural tractor and on its lower side, teeth or blades are rigidly affixed extending towards the bottom. In order to prevent the turning assembly comprised of the rotary plate and the hoeing teeth from coming into contact with the trunks of the plants, trees or shrubs, a sensor is mounted in front of and at a distance from the hoeing head, in a manner so that when this sensor encounters a trunk of a tree or shrub, it is pushed back and controls a hydraulic device that ensures the lateral retraction of the hoeing head as it approaches this trunk. After passing the trunk, the sensor returns to its initial position and controls the hydraulic device which replaces the hoeing head in the inter-vinestock or inter-trunk areas.
These machines which allow a mechanization of the plowing work done between the vinestocks or between the trunks of the trees or shrubs of the plantations, have however several notable disadvantages.
None of them has a multifunctional character.
Taking into account the fact that their hoeing head moves aside as it approaches the trunks and repositions itself after passing them, the duration of this movement and the displacement of the machine allow more or less sizeable zones that have not been worked to remain at the trunks of the shrubs or trees.
Their sensor can be activated during the encounter of undesirable plants that are resistant to bending, which causes the retraction of the hoeing head and the creation of zones that have not been weeded.
The use of a sensor and a hydraulic device for control of the withdrawal of their hoeing head complicates their manufacture and their maintenance and unfavorably influences their cost price.
In the document FR-2.109.237 A, a mowing and hoeing machine consisting of a working head of the type mentioned above is described, above which a flat disk is arranged that is free in rotation and has a diameter slightly greater than the diameter of the working surface of the tools, in a manner such that upon encountering a vinestock, the flat disk is supposed to roll on the vinestock, in a manner that allows a mowing or hoeing action very close to the vinestock and without harming it. However, the encounter of this disk with the trunks of the shrubs generates shocks having a harmful effect on the plant; for example, at certain periods of the year, the vine is very sensitive to vibrations and shocks causing a large percentage of the buds to fall. In addition, these shocks can cause the hoeing head to bounce, while in the best of cases, the turning disc only rolls over a reduced portion of the periphery of the trunks of the shrubs, in a manner so that the work around these trunks can not be regular.
In the other hand, the rotation of the tools at an increased speed causes a movement of the ground and the pulled-out plants and this moving mass can perform the function of a friction clutch causing the flat disk to rotate at a speed that is more or less sizeable. During the encounter with the vinestock, the existence of a relative speed between the vinestocks and the flat disk turning can inflict harm on these vinestocks or cause the working head to bounce, increasing the risks of laceration of the vinestocks and irregularity in working the ground around them, these injuries can be aggravated when the working head moves on banked ground.
Because of the above disadvantages, the speed of progression of the machine must necessarily be relatively slow.